A corneal reflection method has been widely used as a technology for inferring a direction of a line of sight. In the corneal reflection method, a direction of a line of sight is inferred using a reflection image formed on a surface of a cornea of an eyeball obtained by radiating infrared light onto the eyeball (which will also be referred to as a “corneal reflection image” below) or an image obtained by imaging a pupil thereof using infrared light. However, when a direction of a line of sight of a user wearing glasses is to be inferred, infrared light radiated onto the user's eyeball is reflected on a surface of the glasses, and a reflection image thereof serves as an outlier (a pseudo bright spot) which hinders a corneal reflection image or a pupil from being observed.
Thus, Patent Literature 1 discloses, for example, a method of removing an outlier other than a corneal reflection image by controlling on- and off-states of a voltage of a liquid crystal panel on a front side of an imaging device to cause only light with a predetermined polarization direction or light beams with all polarization directions to be transmitted therethrough.
In addition, individuals can be identified as in iris authentication or awakened states or health states of individuals can be ascertained by imaging eyeballs and performing image processing on the images. However, in a case in which infrared light is radiated toward a user who is wearing glasses, light reflected on a surface of the glasses becomes an outlier, and thus it may be difficult to observe the user's pupil, iris, and the like, as in a case in which a direction of a line of sight is to be inferred.